Percussive rock-drill.



W. G. STEPHENS. PERGUSSIVE .ROGK DRILL. APPLICATION FILED AUG. 1. 1908.

2 8HEETBSHEET l.

, Patented Aug". 10, 1909.

W. G. STEPHENS. PEROUSSIVE BOOK DRILL. APPLICATION FILED AUGL'I. 1908.

Patented Aug. 10, 1909. 2 SHEETS-SHEET 2.

N Q m: w\ R Q N N 1 5. F 0 5 WILLIAM CHARLES STEPHENS, OF CORNWALL,ENGLAND.

rnncussrvn noon-DRILL.

Specification of Letters Patent.

Patented Aug. 10, 1909.

Application filed. August 1,1908. Serial No. 446,449.

To all whom 'it may concern:

Be it known that 1,.WILLIAM CHARLES STEPHENS, a subject of the King ofGreat Britain, residing at Carn Brea, Cornwall, England, have inventednew and useful. Improvements in or Connected with PercussiveRock-Drills, of which the following is a specification.

My invention relates to percussive rock drills of the hammer type and tothat class of such drill wherein the feed motion is automaticallyeffected by air pressure, the chief object of my invention beingtoconstruct a drill of this class which is considerably shorter thandrills of the same class as heretofore constructed and wherein the feedcylinder has been arranged behind and in alinementwith the hammercylinder, the advantages of a short drill being not only that the drillmay be worked in more cramped and narrow places orgalleries than thelonger class of drill but that a relatively lon hole 4 can be bored bymeans of a single drill bit and without the necessity for moving thesupport or fixing for the drill.

According to my invention the feed cylinder instead of being arrangedbehind and in alinement with the hammer cylinder is arranged parallel orside by side with the same and preferably beneath it, the-said feedcylinder being-adapted to slide upon a suit able cradle to which is alsoanchored orsecured the rod of the piston withinthe feed cylinder.

ofenable my invention to be fully understood I will describe it byreference to the accompanying drawing, in which Figure 1 is alongitudinal sectional elevation of a percussive rock-drill constructed5 according to this invention and ada ted. to carry a hollow drill forthe supply 0 water to the bore-hole. Fig. 2 is a sectlona-l plan,

and Fig. 3 a sectional side elevation thereof. Figs. 4 and 5 arerespectlvely a front-end view and a rear endsectional View of the drill.Fig. 6 is a. section on the line 6- 6- Fig. 2, and Fig. 7 is a sectionon. the line 7'?, Fig. 4.. Fig. 8 is a section on the line 8-8, Fig. 2and Figs. 9 and 10 are respectively sections on the lines 9- -9 and10-10 Fig. 8. Fig. 11 is a similar View to Fig. 10 showingadifierent'positi0n of the parts.

Fig. 12 is a section on the line 12 12,Fig.-

1 and, Fig. 1-3 is an enlarged section on the line 13-13, Fig. 2. Fig.14 1s a plan of the "cradledetached. Figs. 15 and 16 are views.

.at right angles of a tool for removing the drill bit from its holder.

fa is the main or hammer cylinder, b the .piston thereof, and c thevalve for controlling the supply of motive fluid to the said piston fromthe passage 0' all of which parts are of usual construction.

d is the feed cylinder arran ed parallel with the cylinder a and preferaly beneath it and e is the cradle uponwhich the cylinder 0! is adaptedto slide in uides e, e.

f is the piston of the cod cylinder the, rod f of which is anchored orsecured to a bracket f on the back of the cradle. This piston may be ofany suitable type but is advantageously of the type wherein the pressurefluid acts behind the piston rings to hold them in close contact withthe surface of the cylinder to preventleakage, as shown clearly inFig. 1. The motive fluid is admitted in front of the piston f through aport f from a distributing tap or cook hereinafter described, so thatthe pressure acting against the said piston-and the front of the feedcylinder serves to push the said cylinder together with the hammercylinder 7 forward.

The cradle e is not permanently fixed to the support '9 for carrying thedrill but is made movable thereon so that when the hammer and feedcylinders have been moved forward to an extent which is limited by thelength of the cradle, the said cradle, which is normally locked to itssupport may be temporarily released therefrom to allow of 7 its beingpushed forward upon the said support to permit of the cylinders againbeing fed forward in the cradle to increase the depth of the hole beingdrilled. It will thus be understood that a hole may be drilled thelength of which is practically twice as great as -the amount of movementprovided for in the. cradle, and this without changing the drill bit, asduring the time that the cradle is being pushed forward, as hereinbeforedescribed, the drill bit will be hearing against the back of the .holeand so prevent the :cylindersfrom being pushed forward with the cradle.I

' ,Any suitable means may be provided for locking the cradle e to itssupport 9. In practice I 'find it advantageous to provide in conjunctionwith the cradle guides e, c a

tions 12?, k formedon the si e of the cradleas shown, clearly in Fig.14, the said bolt, when tightened up, looking the cradle and support 9together.- The bolt 7L has arranged in conjunction with it a spring 2',the normal tendencyof which is to disengage the serratedv head /L fromthe cradle serrations h" when the tightening nut 2" is released, inorder to obviate the necessity for moving the bolt by hand, and thetightening bolt [2, and nut 2" are provided with a quick thread so thata slight turn of the said nut will be suflicient to allow of-thedisengagement.

The cradle support 9 is advantageously formed with a conical base 9which fits into a correspondingly shaped socket j on the bracket 7" bymeans of which the drill is carried on the usual supporting bar or stand70, this arrangement of cone and socket allowing of the ready adjustmentof the drill.

The bolster Z against which the hammer piston Z) operates and whichcarries the drill bit m is rotated to twist the bit by means of gearing,a series of teeth at around the bolster being engaged by a gear wheel amounted on a telescopic shaft 0, the telescopic sections 0, 0 thereofbeing secured respectively to the said gear wheel a and to the bracket fupon the cradle 0 so that the shaft 0 will extend as thefeed proceeds.The two sections of the telescopic shaft are connected together in such'a manner that while capable of moving longitudinally there is norelative n iotion of rotation between them. In the drawings this iseffected by a key 0 on the part 0 engaging a key-way 0 in the part 0 Theportion 0' of the shaft 0 carried by the cradle is provided with ahandle or lever 79 for imparting rotary motion as the drilling proceeds.

For supplyingwater to the hollow drill m I advantageously provide thefollowing ar-.

rangement, that is to say, around the bolster Z within the head a-I forma recess 9 into which the water is delivered through a passage 'r' fromthe distributing tap or cock hereinafter described. In the said grooveor channel 91 arrange a ring 8 grooved on its inner and outer surfaces,the said grooves being connected by holes 8 .so that water passing fromthe passage rfiows around the outer groove and through the holes 8 tothe inner groove, holes t being provided in the bolster so that theWater can then flow into the central. hole t communicating with the bitm. The ring 8 is located between two pieces of packing u, u a packinggland u also nterlng the recess 9 tomaintain the said packings tight.around the bolster. o is a groove formed in the head a and open to'theair by holes 'v, c so'that any leakage of water past the packings u, ucan escape. The chamber a in the head a in which the teeth 71, on thebolster are located is also provided with a piece of packing w and metalwasher to to prevent access of any water.

For controlling the supply of pressure fluid to the main piston and feedpiston and of water to the drill bit m I employ a single tap or cock whaving inlets w and m for the supply of the pressure fluid and waterrespectively. The plug w of the cock is formed with recesses w and w,the recess of being designed to connect the inlet a," with the port mwhich is formed in one with the ports 0 and f for supplying the main andfeed cylinders while the recess m is designed to bring the inlet .22into communication with the passage 1' to the drill bitm. The recess 00is so arranged relatively with the recess 93* that when the plug as isturned slightly, when starting the drill, the water supply is firsteffected, the water passing to the cutting edges of the bit before thedrill commences to work, and thus insuring the free flow of water takingplace before striking the rock tobe drilled so that out portions of rockare prevented from choking the hole in the bit. By further rotation ofthe plug the pressure fluid is then admitted to the cylinders a and dand the drill then commences to operate the water being full on. If itis found that the water supply is excessive I provide a screw valve orregulator w in the inlet m so that'the supply can be diminished. Toprevent water leaking around the drill shank within the drill holderportion of the bolster, I provide a conical hole m in the said holder,and I form the said bit' with a correspondingly shaped shank m", whichwhen jammed back into the hole m, makes a water tight joint. For theextraction of this form of drill bit from the holder, I 'fnploy a collarmion the drill bit, and I einploy a forked wedge m Figs. 15 and 16,which is placed between the said collar, and the nose of the drillholder the fork embracingsthe drill shank. By a simple tap with ahammer'the wedge forces the collar away from the drill holder, and soextracts the drill bit.

4 Although I have described the tap a: in combination with my improveddrill, the arrangement for preventing leakage between the bit and itsholder and the means for extracting the bit from the holder I make noclaim to these in this specification as they form the subject of anotherapplication of even date herewith Serial No. 446,450.

I sometimes apply to the rear end of the hammer cylinder a clip a whichembraces either the rod of the feed piston, or the portion 0? of thetelescopic shaft 0, in the drawings it. is shown embracing the latter,the chief function of this clip being to support the weight ,of thecylinder ato prevent its sliding through the cradle 0 when changing bitswhile boring holes at angles below or above the horizontal, and thusobviating the necessity for the operator to hold up the weight of themachine when changing the drill bit, or pointing the drill to thevarious angles; 2 is a screw for gripping the jaws of the clip on therod 0 The said clip also acts as a brake when boring down holes in softrock, to prevent too rapid feeding under .vided with lateral serratedportions, and

a piston in the feed cylinder operatively connected with the cradle, ofa support for the cradle provided with clamping devices having serratedportions for engaging the serrated portions of the cradle, substantiallyas described.

2. In a rock drill, the combinationwith the hammer and feedcylindersarranged side by side, a cradle havin a sliding enga ement withthe feed cylinder, and provi ed with lateral clam engaging portions, anda piston in said eed cylinder, operatively connected with the cradle, ofa supporting bar, a bracket provided with a, clamp for engaging thesupporting bar, and a vertically disposed downwardly tapered socket, acradle support, located beneath the cradle, and provided with a taperedbase pivotally engaging said. socket, means for securing said cradlesupport and bracket together,

and a clampingbolt disposed transversely of the cradle, and secured tosaid cradle support, said bolt being provided with clamping means foradjustably engaging the lateral portions of the cradle, substantially asdescribed.

3. In a rock drill, the combination with the hammer and feed cylindersarranged side by side, a cradle having a sliding engagement with thefeed cylinders, and pro-.

vided with lateral clam engaging portions, and a piston in said eedcylinder operatively connected with the cradle, of a supporting bar, abracket provided with a clamp for engaging the supporting bar, and avertically disposed downwardly tapered socket, a cradle support, locatedbeneath the cradle and provided with a tapered base pivotally engagingsaid socket, means for securing said cradle support and brackettogether, a clamping bolt extending through said cradle support,transversely of the cradle, and having serrated clam ing means forengaging serrated portions 0 the cradle, and a spring connected withsaid bolt and normally tending to disengage the serrated portions ofsaid bolt and cradle, substantially as described.

4. .In a rock drill, the combination with the drill cylinder and feedcylinder arranged side by side, the drill cylinder being provided with arotatable drill su port, a. cradle supporting said cylinders and havinga sliding engagement therewith'and a piston in said feed cylinderoperatively connected with said cradle, a rotatable sleeve carried bythe drill cylinder, and operatively connected with the drill sup ort forrotatin the same, a rotatable sha t secured to sai cradle connected tosaid sleeve for rotation therewith and having a longitudinal slidingenga ement with said sleeve, and operative mec anism for rotating saidshaft, substantially as described.

5. In a rock drill, the combination with the drill cylinder and. feedcylinder ar-' ranged side by side, the drill'cylinder being providedwith a rotatable drillsupport, a cradle supporting said cylinders andhaving a sliding engagement therewith and a piston in said feed cylinderoperatively connected with said cradle, a rotatable sleeve carried b thedrill cylinder, and operatively connecte with the drill su port forrotatin the same, a rotatable sha t secured to sai cradle connectedtosaid sleeve for rotation therewith and having a longitudinal slidingengagement with said sleeve, means for rotating said shaft and anadjustable friction clamp secured to the cylinders, and frictionallyengagin the said shaft, substantially as describe WILLIAM CHARLESSTEPHENS.-

Witnesses! HOWARD Fox, W. H. DANIELL.

